Counterbalance



Aug 17, 1937. H. .1. BuRNlsH 2,090,589

COUNTERBALANCE Filed July 5, 1935 2 Sheets-Sheet l -COUNTERBALANCE Filed July 5, '1953 2. Sheets-Shea;c 2

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Patented Aug. 17, 1937 PATENT OFFICE ooUN'rERBALANCE- Howard J. Burnish, Sewickley,

Pa., assignor, by

mcsne assignments, to The National Supply Company vof Delaware, Toledo, Ohio, a corporation of Delaware Application July 5, 1933, Serial No. 679,026

-9 Claims.

My invention relates more particularly to counlterbalances for crank shafts applicable to counterbalancing varying heavy loads to which well drilling and pumping apparatus are subjected.

The mainobject of my invention is to provide a counterbalance applicable to crank shafts which may be required to operate at comparatively high uniform speeds or comparatively low speeds having a pulsating shock to counterbalance. One l feature of my invention is the means employed in adjusting'counterweights without the requirement of hard manual labor or heavy cumbersome tools.

Another object of my invention is to' provide means to definitely adjust to and hold counterweights at the static, the maximum kinetic or intermediate kinetic balanced positions with vernier precision of adjustment.

Another object of my invention is the provision of new and more secure means for attaching-f counterweights to the perimeter of acrank member. l

Another object of my inventionA is to provide a means for changing the moments or inertia effects of the lcounterweights, creating'a balanced condition between the load and the source of power without removing the weights from the crank element.

A further object is to provide a counterweightand crank structure that is simple in design, economical to manufacture and durable in character.

Other objects will appear from the following description.

In theaccompanying drawings I have illus- 35 trated two practical embodiments of the principles of my invention, and the embodiment -second described is preferable as for commercial use.

Referring to the accompanying drawings, Fig. 1

is a side elevation of one embodiment of the 40 principles of my invention showing the crank arm, the eccentric disk and the counterweights mounted on. the latter.

Fig. 2 is a sectional view taken along the irregular line 2-2 in Fig. 1. l

45 Fig. 3 is a development of a cross sectional view taken along the arcuate line 3-3 in Fig. 1.

Fig. 4 is a side elevation showing another embodiment of the principles of my invention.

Fig. 5 is a'sectional view of the'same taken 50 along-the line 5-5 in Fig. 4.

Fig. 6 is a broken and enlarged section taken along the line 6-6 in Fig. 4.

Fig. 7 is an enlarged perspective of one of th'e washers used in connection with the clamping 55 bolts.

Referring first to Figs. 1 to 3 inclusive, I0 represents the crank shaft normally rotated by a suitable source of power, not shown. II represents a combined crank arm and disk member which is mounted on and rendered rigid relative to the shaft I0 as by key I2. The element II is .preferably an integral casting comprising the crank arm I3 disposed radially of the shaft and the circular disk I4 disposed eccentrically of the shaft. The crank arm I3 is given a greater thickness than the body of the disk' I4, as clearly illustrated in Fig. 2, the thinner web I6 of the disk, indicated by dotted lines in Fig. 2, being braced by the diametrically disposed rib 2I disposed along the center line 22 of the disk and at right angles to the crank arm.

Adjacent the peripheral edge of the disk and on each side thereof there is formed an annular groove I8, thus providing the disk with an annular T-shaped peripheral edge portion I9. The 20 outer edge of the disk is provided with a plurality of transversely disposed semi-circular slots 20 equally spaced around the circumference of the disk, forming a gear-like perimeter. The numeral 23 indicates the axis of rotation of the disk and crank, which is also the center of rotation of the shaft I0, which center lies in the axis 24 which is at right angles with the axis of the crank I3.

Thus theI disk provides a maximum moment arm from the center of rotation 23 to the point of the periphery of the disk most distant from the shaft and a minimum arm from the center 23 to a point on .the opposite side of the periphery of the disk. It is thus evident that all the corresponding intermediate positions along both sides of the periphery of the disk between the maximum and the minimum moment arm of the disk constitute equal moment arms of varying lengths. Therefore equal weights placed at corresponding positions about the periphery of the disk willset up a balanced kinetic condition with respect to the center of rotation of the disk.

26 represents arcuate weights formed of two duplicate and complementary parts 2-1 and 2B, each part having a body portion 29 and an inner end portion 30, which end portion is provided with an arcuate recess or groove 3| formed on its inner face to receiveone side of the T-shaped periphery I9 of the disk, as shown in Fig. 2, the inturned iiangcs 32 of the weight parts engaging the neck of the T and thus the parts 21 and-28 clasp the peripheral portion of the disk between them. The weight parts 21 and 28 are clamped together by the bolts 33 which extend through registering holes in the body portions 29 of the weight parts. The inner portions 30 of the weight parts are provided with a series of transverse holes 34 whose centers are disposed along the 5 peripheral edge of the disk when the weights parts are assembled thereon.

'Ihe spacing between the consecutive holes 34 in the Weight parts diiers from the spacing between the consecutive slots 20 in the edge of the l disk, and the spacing of the bolt holes and the slots is so related that only a. limited number of the holes 34 will register with slots 20 so that the bolts 35 may be inserted through said holes and engage said slots at each position of the p weights when they are secured to the disk. Thus in the drawings the bolt holes are shown spaced farther apart than are the slotsv and the bolts'- 20 slots in the disks the minimum unit of arcuate distance may be varied.

It is evident that the described Vernier arrangement of Weights may be adjusted and positioned with respect to each other and lwith re- 5 spect to the disk with an accuracy whose precision is determined by the manufacturing tolerance of the device.

When the weights are placed in the dotted position shown at 26 in Fig. 1 they balance the weight of the crank arm and of the eccentric 40 disk and the device then functions as a ilywheel and may be rotated at high speed. v

Again, this arrangement of the weights is employed when the pitman has been detached from the crank pin positioned in one of the holes l5 r as when hoisting or withdrawing tools from `a well.

When the pitman is attached to a Wrist pin positioned in one of the holes l5 and the loads on the pitman are pulsating the weights are adjusted in opposite direction about the periphery of the disk to selected positions of equal moment arms which balance the pulsating shocks and eliminate vibration.

The eccentrically positioned disk provides a means for arranging or positioning the counterweights 'therearound whereby the mass of one of the weights may have an equal or balanced moment arm with respect to the other weight or they may be so positioned about the periph- 0 ery of the disk so as to produce moment arms of Varied lengths. 'I'his feature provides an arrangement that enables the pulsating load that is to be compensated for to be accurately balanced by means of two individually' adjusted weights in combination with the crank arm. When the pulsating load to be balanced precedes the pitman in time and the counterweight required to balance thisload is less than that available, one of the counterweights maybe 0 placed adjacent to the longitudinal axis of the crank arml so that its moment arm in relation thereto is `very small, while the other weight may be positioned 90 ahead of the crank arm, at which position it would have a maximum 5 moment arm. The resultant load of the balancing weightswould then precede the pitmanv and the crank arm in proportion to the respective masses in the moment arms of the counterweights. With this structure the load to be compensated may lead or lag the pitman in time for a considerable number of degrees and still be compensated by the two counterweights of la fixed and determinable mass needing no provision for increasing or decreasing their actual weight,v which provision must necessarily be made on other counterbalanced structures to ac-l complish the same results.

On the other hand if my disk were concentrically mounted on the shaft I0 the counterweights could not produce a condition of a static balance of the mechanism as previously described.

The bolts 33 function to clamp the weight parts together in rigid relation, whereas the bolts 35 perform a dual function, assisting to clamp the weight parts together but also maintaining the weights in the positions to which they have been adjusted about the periphery of the disk. The bolts 35 are subjected to shear strain between the weights and the disk, but should they be sheared off the flanges 32 will continue to hold the weights on the wheel, preventing themv from being thrown from the wheel by centrifugal force which might resultin serious damage. i

To position the counterweights about the wheell elements the bolts 35 are removed and the disk is slowly rotated while the weights remain ysuspended at the lower portion of the disk, and when the disk and a weight are at the desired relation, the bolts 35 are replaced and tightened to lx the weight in its selected position. This feature of my invention eliminates the use of heavy tools and hard manual labor in placing the weights in their proper position and it is both novel and highly advantageous.`

Referring now to Figs. 4 to 7 inclusive wherein I have illustrated the preferred embodiment of the principles of my invention, 36 represents the combined crank arm and disk and an integral casting which is eccentrically mounted on'and keyed, as at I2, to the shaft l0. Said casting comprises a relatively thickened fan-like portion 31, the heavier crank arm portion 38 being disposed radially of the axis of movement of the disk and provided with the pin holes I5, the relatively thin webs 39 which may be provided with apertures 40 and the heavier perimetral edge portion which is grooved at either side as at IB to form the T- shapedperipheral edge I9 as in the rst described embodiment. The weights 4I are composed of the complementary parts or halves 42 and 43. 'I'he inner faces of the weight parts are recessed at their inner ends to t over the edge portion of the disk 36, as more clearly illustrated in Figs. 5 and 6, and said parts are provided with registering socket lholes 44 in which are xed the pins 45 which extend inwardly into the grooves Il of the disk and have rotatably mounted thereon the annular rollers 46, antifriction bearings 41 q being preferably interposed between the pins and the rollers.

When in place the weight parts are rigidly clamped together and to the disk by means of bolts 48 extending lthrough registeringv holes 49 in the weight parts adjacent to the edge of the disk.

The outer ends of the holes 49 are countersunk or enlarged to form non-circular seats, and 50 are non-round washers mounted on the head-ends of the bolts 48 and fitting in said seats, said washers having squared outer openings to receive the heads of the bolts 48 to prevent their turning.

5 The weight parts are alsb held together by means of pins l extending through registering holes in the weight parts and having their ends provided with washersv 52 and cotter pins 53 occupying the countersunk ends of said holes.

weight parts are usually sumcient and I prefer to provide three spaced apart clamping bolts.

If desired the rollers may be omitted from the pins and shoes substituted.

When the weights are to be adjusted the clamp- ,ing bolts are loosened so that the weights will depend from the lower portion of the disk and the disk is then rotated until it attains its proper relation to one of the weights.

The clamping bolts are then tightened rigidly securing the weight to the disk and the disk is then rotatedv until it attains its desired relation with the second weight which is then clamped rigidly to the disk. When the disks are in their freely suspended condition the disk turns relative to the weights with great ease.

It is obvious that with the last described movement of the principles of my invention great accuracy and nicety of adjustment is obtained in positioning vthe weights relative to the disk.

I claimzv 1. In counterbalance mechanism for use i in connection with a rotary crank shaft, the combination of a circular disk arranged to be mounted on the shaft and provided with a peripheral rim of substantially T-shape cross-section, a two-part l weight mounted on the disk, said `weight-parts.

having complementary faces which mate in surface contact in a plane normal to the axis of the disk and which faces are recessed to provide arcuate surfaces to mate with the convex peripheral edge of thev disk, and said weight-parts having Yinwardly extending portions to engage the sides of the rim of the disk, rollers carried by the inwardly extending portions and engaging the inner arcuate surfaces of the rim of the disk, and clamping bolts disposed substantially parallel with the axis of the disk and engaging registering holes in the weight-parts to hold the weightparts together and on the disk in such a manner as to be wholly supported from the rim of the disk.

2. In a counterbalance device for well pumping apparatus, the combination with a rotary crank shaft, of a circulary disk eccentrically mounted on the crank shaft, a weight, means for pendulously supporting said weight from the periphery of said disk, said weight being freely slidable relative to the disk when the latter is rotated, and means for clamping said weight to said disk.

3. In a counterbalance device for well pumping apparatus, the combination with a rotary crank shaft, of a circular disk eccentrically mounted on the shaft, a plurality of counterweights, 'means for pendulously supporting said weights from the periphery of said disk, said weights being freely slidable relative to the disk when the latter is rotated, and means for clamp- Two sets of rollers for each pair of counter-v periphery of said disk, said we ht being freely slidable relative to the disk w en the latter is rotated, and whereby the said weight may bc circumferentially adjusted at any position on the periphery of said disk, the said means including instrumentalities whereby the said disk may be rotated through any predetermined degree while said weight is pendulously supported therefrom, and means for clamping said weight to said disk.

5. In acounterbalance device for well pumping apparatus, the combination with a rotary crank shaft, of a circular disk eccentrically mounted on the crankshaft, a plurality of counterweights, means for pendulously supporting said weights from the periphery of said disk, said weights being freely slidable relative to the disk when the latter is rotated, and means whereby the said weights may be circumferentially adjusted at any position on the periphery of said disk, the same means including instrumentalities whereby the said disk may berotated through any predetermined degree while vsaid weights are pendulously supported therefrom and one or both of said weights clamped to said disk, and whereby the said disk may be further rotated and another of said weights is clamped thereto.

6. In a counterbalance device for Well pumping apparatus, the combination with a rotary crank shaft, of a circular disk mounted on the crank shaft and provided with a peripheral rim of substantially T-shape cross section, a two-part counterweight, each part having a portion for engagement with one of the inner arcuate surfaces of the rim of the disk whereby said weight may be wholly and pendulously and slidably supported from said disk during relative rotation of parts to the disk.

'7. In a counterbalance device for well pumping apparatus, the combination with a rotary crank shaft, of a circular disk mounted on the crank shaft and provided with a peripheral rim of substantially T-shape cross section, a two-part counterweight, each part having a portion for engagement with one ofthe inner arcuate surfaces of the rim of the disk whereby said weight may be wholly and pendulously and slidably supported from said T-shape' rim during relative rotation of the same and means for clamping the weight parts together and to the disk.

8. In a counterbalance device ,for well pumping apparatus, the combination with a rotary crank shaft, of a circular disk mounted on the crank shaft and provided with a peripheral rim of substantially T-shape cross section, a plurality of two-part weights, each weight part being complementary and having a portion for engagement with one of the inner arcuate surfaces ofthe rim of the disk whereby said weights may be wholly and pendulously and slidably supported from said T-shape rim during relative rotation of the same. and means whereby the said weights may vbe circumferentially adjusted atany position on the periphery of said disk, the said means comprising instrumentalities whereby the said disk may be rotated through any predetermined degree while said weights are pendulously supported therefrom and one or both of said weights clamped to said disk, and whereby the said disk may be further rotated and -another of said weights is clamped thereto.

9. In a counterbalance device for well pumping apparatus, the combination with a rotary crank shaft, of acircular disk mounted on the crank shaft and provided lwith a peripheral rim 'the same, and means for clamping vsaid weight of substantially T-shape cross section, a two-part counterweight, each part having a portion for engagement with one of the inner arcuate surfaces of the rim of the disk whereby said weight may be wholly and pendulously and slidably supported from said T-shape rim during relative rotation of the same, the outer surface of said 

